Known To Unknown: Predicting Unpredictable Forces
Towards Teleoperation With Predictive Force Feedback That Copes With Unknowns
Q.M.F. Van Opstal (TU Delft - Electrical Engineering, Mathematics and Computer Science)
H.J.C. Kroep – Mentor (TU Delft - Corporate Innovations)
G. Lan – Graduation committee member (TU Delft - Embedded Systems)
R.R. Venkatesha Prasad – Graduation committee member (TU Delft - Networked Systems)
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Abstract
Long distance Haptic Bilateral Teleoperation (HBT) is used in applications such as surgery, training, remote operation, and disaster relief. One of the main challenges in these systems is communication delay. When force feedback relies directly on sensors in the remote environment, increasing delay quickly makes the system unstable and hard to control. To overcome this, previous approaches generated force feedback using a local simulation of the remote environment, while providing visual feedback through live video [20]. This reduces timing constraints, but only works when the simulation accurately represents reality. When the robot encounters objects that are not modeled and not visible to the operator, unpredictable forces occur and the system no longer behaves correctly.
This thesis investigates how such unpredictable forces can be handled in delayed HBT. We introduce a method that keeps predictive force feedback through simulation, while correcting the simulation using sensor data from the robot. A small 3D printed attachment was developed to detect unexpected contact events. These measurements are sent back to the operator side and used to update the virtual environment, allowing force feedback to be generated even for unknown objects. The approach was evaluated in a user study with 13 participants under varying delays and visibility conditions. The results show that when visibility is limited, reaction based feedback can be used instead of prediction based feedback. The findings indicate that combining simulation based prediction with remote sensing offers a practical solution for dealing with unpredictable forces in long distance HBT.